Auto merge of #147138 - jackh726:split-canonical-bound, r=lcnr

Split Bound index into Canonical and Bound

See [#t-types/trait-system-refactor > perf `async-closures/post-mono-higher-ranked-hang.rs`](https://rust-lang.zulipchat.com/#narrow/channel/364551-t-types.2Ftrait-system-refactor/topic/perf.20.60async-closures.2Fpost-mono-higher-ranked-hang.2Ers.60/with/541535613) for context

Things compile and tests pass, but not sure if this actually solves the perf issue (edit: it does). Opening up this to do a perf (and maybe crater) run.

r? lcnr

Author: bors

clippy_lints/src/pass_by_ref_or_value.rs

@@ -14,7 +14,7 @@ use rustc_hir::{BindingMode, Body, FnDecl, Impl, ItemKind, MutTy, Mutability, No
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::adjustment::{Adjust, PointerCoercion};
 use rustc_middle::ty::layout::LayoutOf;
-use rustc_middle::ty::{self, RegionKind, TyCtxt};
+use rustc_middle::ty::{self, BoundVarIndexKind, RegionKind, TyCtxt};
 use rustc_session::impl_lint_pass;
 use rustc_span::def_id::LocalDefId;
 use rustc_span::{Span, sym};
@@ -151,7 +151,7 @@ impl PassByRefOrValue {
             match *ty.skip_binder().kind() {
                 ty::Ref(lt, ty, Mutability::Not) => {
                     match lt.kind() {
-                        RegionKind::ReBound(index, region)
+                        RegionKind::ReBound(BoundVarIndexKind::Bound(index), region)
                             if index.as_u32() == 0 && output_regions.contains(&region) =>
                         {
                             continue;

clippy_utils/src/ty/mod.rs

@@ -21,7 +21,7 @@ use rustc_middle::traits::EvaluationResult;
 use rustc_middle::ty::adjustment::{Adjust, Adjustment};
 use rustc_middle::ty::layout::ValidityRequirement;
 use rustc_middle::ty::{
-    self, AdtDef, AliasTy, AssocItem, AssocTag, Binder, BoundRegion, FnSig, GenericArg, GenericArgKind, GenericArgsRef,
+    self, AdtDef, AliasTy, AssocItem, AssocTag, Binder, BoundRegion, BoundVarIndexKind, FnSig, GenericArg, GenericArgKind, GenericArgsRef,
     GenericParamDefKind, IntTy, Region, RegionKind, TraitRef, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable,
     TypeVisitableExt, TypeVisitor, UintTy, Upcast, VariantDef, VariantDiscr,
 };
@@ -826,7 +826,7 @@ pub fn for_each_top_level_late_bound_region<B>(
     impl<'tcx, B, F: FnMut(BoundRegion) -> ControlFlow<B>> TypeVisitor<TyCtxt<'tcx>> for V<F> {
         type Result = ControlFlow<B>;
         fn visit_region(&mut self, r: Region<'tcx>) -> Self::Result {
-            if let RegionKind::ReBound(idx, bound) = r.kind()
+            if let RegionKind::ReBound(BoundVarIndexKind::Bound(idx), bound) = r.kind()
                 && idx.as_u32() == self.index
             {
                 (self.f)(bound)